2003 explorer V6 engine knock.

spun rod bearing causeing piston to valve slap,bad wrist pin on piston rod.

Problem found. Brought car to mechanic shop for diagnosis. Pulled out his diagnostic tools, hooked them up, and started the engine. The engine blew cracking the block above the starter right there in the bay at idle. Mechanic suspects the piston became disconnected from the rod. Anyone else heard of a similar problem with these engines? I'm 60 and it's not like I have ever drove it hard. In fact, the mechanic said it's the cleanest inside of an engine he's ever seen (due to frequent oil changes)

Dang,tough luck.

Is the knock there during start up only? Or is it a rattle type noise on acceleration and usually do it going up hills? If you did an oil change and replaced tensioners,I would assume your noise is on top and not a lower bearing knock. My '02 does that periodically. The oil journals in my explorer were clogged with oil sludge causing the timing chain tensioners to not keep proper pressure on chains. I did an "engine flush" using Pyroil engine flush. When engine oil is hot, pour in Pyroil engine flush into engine "BEFORE" changing oil. Let engine idle for 5-8 minutes. DO NOT drive!!! Perform oil and filter change. I use Valvoline Maxlife oil religously. This cleans oil journals. I also noticed better fuel economy and engine performance after doing this. I do it to my '02 every 30,000 miles. Currently has 128,000 now and all is fine!!!

Dave: Keep in mind I'm 60 and learned what little knowledge I have working on engines manufactured in the 40's and 50's when being a kid meant taking engines apart under a tree and fixing them. Back then, air, fuel, and spark operated the engine and the word computer had not been invented yet. The original noise sounded like a stuck lifter on the drivers side. I removed and cleaned all the lash adjusters, but it did not solve the problem. There was no miss in the engine while running and the location of the knock could not be determined with a stetiscope (sp?) or the use of an old timing light counting the blicks of the light between the knock. Now wanting to be defeated I pulled the engine to look at the rear tensioner (bad design) and replaced them although they looked good, worn a little but good. When the engine blew at idle right above the starter leaving a golf ball size hole just above the started, I had it. Ordered a jasper reman. engine, dropped it in, crated up the old one for return without even wanting to know what gave. I have to say the Ford engine design for the V-6 with a gear on the rear of the engine is a bad design. I still have a '51 Ford with a flathead v-8 which runs great. After owning it for 40 years all I have ever done to it is change the water pump a few times and the drivers side axel shaft (drive wheel) as they seem to sheer off occassionally about a foot into the housing.

Have one in the shop now .with bent rod